What has Canada done about acid rain?

In 1985 the governments of Canada and the seven eastern provinces joined forces to take action on reducing sulphur dioxide, the major contributor to acid rain. They launched a program to cut sulphur dioxide emissions in the eastern provinces in half by 1994. It was hoped that this action would reduce the deposition of sulphates in rain and snow in eastern Canada from levels as high as 40 kg per hectare per year (kg/ha/yr) to no more than 20 kg/ha/yr, a level that would cause considerably less damage to ecosystems.

Canada was more than successful in meeting its target. By 1994, sulphur dioxide emissions in eastern Canada were 54% lower than 1980 levels.

Since about half of the acid rain in eastern Canada comes from American sources, the cooperation of the U.S. was also needed. In 1990, the U.S. launched action to reduce emissions of sulfur dioxide by amending its Clean Air Act and, in 1991, by signing the Canada-U.S. Air Quality Agreement. By 1996, U.S. emissions had declined to about 27% lower than they were in 1980, and by 2010, they should decrease by a total of 40%.

With decreasing emissions, the amount of acid rain has also decreased. In the decade between the early 1980s and the early 1990s, the area of eastern Canada receiving more than 20 kg/ha/yr of sulphate in rain and snow had declined by 61%.

Remaining Challenges

Despite this progress, an acid rain science assessment conducted in the mid-1990s showed that some serious problems remained:

• More action was needed to fully protect Canada's ecosystems. Without further emission reductions beyond those required under the 1991 Air Quality Agreement, scientists estimated that an area of some 800,000 square kilometres, extending from central Ontario through southern Quebec and across much of Atlantic Canada, would still be receiving more sulphate than its natural systems could tolerate. Back in 1985, when the original targets for reducing sulphur dioxide were set, the effects of acid rain on lakes and other ecosystems were not well understood. Since then, many eastern Canadian ecosystems have been found to be more sensitive to acid rain than scientists had originally thought. Atmospheric modelling conducted as part of the science assessment showed that a further 75% reduction in sulphur dioxide emissions (beyond current commitments) in targeted regions of eastern Canada and the U.S. would be necessary to protect all of the 95,000 lakes in this area.
• Some acidified lakes showed signs of recovery, but many more did not. Of 202 lakes that were studied between the early 1980s and the mid-1990s, 33% had reduced levels of acidity while 56% showed no change and 11% actually became more acidic. The greatest improvements were seen in the Sudbury area, where lakes had been very badly damaged. Here, fish populations rebounded and fish-eating birds, such as loons, increased. However, no substantial wildlife recovery had been seen beyond the Sudbury area. The least improvement was seen in Atlantic Canada, although lakes in this region were never as highly acidified as those in some parts of Ontario and Quebec.
• Reducing nitrogen oxides was becoming more important. If nitrate deposition continued at current levels, its contribution to acidification would eventually erode the benefits gained from the reductions in sulphur dioxide. Because nitrogen oxides also contribute to ground-level ozone, the main ingredient in smog, reducing these emissions would also help to improve air quality.

As a result, on October 19, 1998, federal, provincial, and territorial Energy and Environment Ministers signed The Canada-wide Acid Rain Strategy for Post-2000. The Strategy laid the framework for how Canada would manage acid rain in the future. The primary long-term goal of the Strategy is to achieve critical loads (or the threshold level) for acid deposition across Canada.

The Strategy is currently being implemented. Its key commitments are:

• to seek further SO₂ emission reductions in the U.S.;
• to establish new SO₂ emission reduction targets in eastern Canada (Ontario, Quebec, New Brunswick and Nova Scotia);
• to ensure adequate acid rain science and monitoring;
• to prevent pollution;
• to keep clean areas clean; and
• to report annually on emissions and on progress.

The Strategy builds on the work of the multi-stakeholder "Acidifying Emissions Task Group." The Task Group released its report, Towards a National Acid Rain Strategy, in October 1997.

Towards a National Acid Rain Strategy
The Canada-Wide Acid Rain Strategy for Post-2000

What is Canada doing, now that the Strategy has been signed?

In 1999, the first year after the signing of the Acid Rain Strategy, federal, provincial and territorial governments focused their attention on a review of acid rain science and monitoring programs. The review was a specific requirement under the Acid Rain Strategy, and was conducted with the goal of "ensuring the capability to assess both the degree of environmental improvement achieved and the adequacy of the control programs". The review identified a number of gaps in existing monitoring networks and research activities and made recommendations to rectify them.

Shortly after the review, Environment Canada announced an increase in funding for its acid rain science and monitoring program over a five-year period. The increased funding has ensured the maintenance of air and lake monitoring activities and has enhanced deposition monitoring and research. These improvements have addressed most of the deficiencies identified in the science review.

The Strategy's commitment to establish new targets and schedules for SO₂ emission reductions in Ontario, Quebec, New Brunswick and Nova Scotia has also been achieved. In 2000 and 2001, these provinces announced new emission targets as follows:

* a proposed policy change in Ontario would advance this timeline to 2010

Implementation of the acid rain strategy is overseen by the Acid Rain Work Group, a federal-provincial committee under the auspices of the Canadian Council of Ministers of the Environment (CCME). Details on progress can be found in the annual progress reports prepared for Energy and Environment Ministers.

Annual Progress Reports on The Canada-Wide Acid Rain Strategy for Post-2000

Current priorities under the Strategy include formalizing the new targets for emission reductions in eastern Canada through federal-provincial agreements, pursuing further U.S. emission reduction commitments, and conducting further scientific work on the role of nitrogen in acidification and base cation depletion. An acid rain science assessment is tentatively scheduled for 2004.

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